Question - are there hot girls on 4chan? Could a 4chan shirt act as a pick up line? Because whenever I want to meet people at the bar, concert, etc. all I have to do I wear a Chive shirt and I've suddenly got more friends than I know what to do with.

If you have to wear a website's t-shirt in order to pick up a girl (who is more than likely an attention whore for a bunch of other guys on your forum or whatever the hell it's even called) then you really should work on your social skills, perhaps log off the Chive.

To answer your question - who knows whom is actually using 4chan because it's all anonymous, unless your question is if there are pictures of hot girls on the site. In which case, yes. There's pictures of hot girls on Reddit as well. Oh and on Camaro5. Oh and literally everywhere else on the internet.